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| author | Alexander Kuleshov <kuleshovmail@gmail.com> | 2016-01-26 22:12:10 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-01-30 11:22:48 +0100 |
| commit | a4733143085d6c782ac1e6c85778655b6bac1d4e (patch) | |
| tree | e9bfa3650d7a7be8e56a6d53a5cad024c86a60d2 | |
| parent | 5e9ebbd87a99ecc6abb74325b0ac63c46891f6f3 (diff) | |
| download | lwn-a4733143085d6c782ac1e6c85778655b6bac1d4e.tar.gz lwn-a4733143085d6c782ac1e6c85778655b6bac1d4e.zip | |
x86/boot: Simplify kernel load address alignment check
We are using %rax as temporary register to check the kernel
address alignment. We don't really have to since the TEST
instruction does not clobber the destination operand.
Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Popov <alpopov@ptsecurity.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1453531828-19291-1-git-send-email-kuleshovmail@gmail.com
Link: http://lkml.kernel.org/r/1453842730-28463-11-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/head_64.S | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index ffdc0e860390..7c21029cb733 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -76,9 +76,7 @@ startup_64: subq $_text - __START_KERNEL_map, %rbp /* Is the address not 2M aligned? */ - movq %rbp, %rax - andl $~PMD_PAGE_MASK, %eax - testl %eax, %eax + testl $~PMD_PAGE_MASK, %ebp jnz bad_address /* |